Tile Engine Collision

Question

Okay, so, I am making a small tile-based digging game, now I want to do collision. How would I go about doing this correctly? I know how to check if the player collides with a tile, but I don't know how to actually make the player stop when it hits a wall.

This is the game, I got 20x20 tiles here.

This is the code I'm using atm:

            foreach (Tile tiles in allTiles)
        {
            if (ply.rect.Intersects(tiles.rect))
            {
                if (tiles.ID != -1 && tiles.ID != 1)
                {
                    if (ply.X > tiles.X)
                    {
                        Console.WriteLine("Right part.");
                        ply.X = tiles.pos.X + 30;
                    }

                    if (ply.X <= tiles.X)
                    {
                        Console.WriteLine("Left part.");
                        ply.X  = tiles.pos.X - 30;
                    }

                    if (ply.Y > tiles.Y) 
                    {
                        Console.WriteLine("Bottom part.");
                        ply.Y = tiles.pos.Y + 30;
                    }

                    if (ply.Y <= tiles.Y) 
                    {
                        Console.WriteLine("Upper part.");
                        ply.Y = tiles.pos.Y - 30;
                    }
                }
            }
        }

Answer 1

What type of collision detection are you using?

If your using Rectangles and the '.intersects' method you can always declare a bool to make sure your character is touching the floor. If he isn't you apply a Gravity Vector to make it fall to the next Tile with a different Rectangle so when he hits it he's going to stop falling.

If you want to block him from side to side just test to see which side of the rectangle he is touching and block him from moving on the 'X' axis. E.g if he is going right and intersects with the left part of a rectangle, block is 'GoingRight' movement.

    if(myCharacterRectangle.Intersects(tileRectangle)
    {

        if(myCharacterPosition.X > (tilePosition.X)
       {
         //You know the character hits the Right part of the tile.
       }

        if(mycharacterPosition.X <= tilePosition.X)
       {
         //You know the character hits the Left Part of the tile.
       }

    }

And same goes for the Position.Y if you want to test the Top or Bottom.

If you want to use Pixel by Pixel collision detection using Matrices I know a good tutorial here. The detection will return a 'Vector2(-1,-1)' if there is no collision. If there is a one the method will return the coordinates of the collisions which makes it even easier to determine what part of the tile your character is touching.

Hope this helps. Good Luck with your game.